You should ask yourself one question, "What if the next deer I see is a buck of a lifetime?" Do you take a chance of losing a deer like that from a dull head?
What I don't get is.....why you think the re-used head has to be "dull".
And....to answer this question.....I shot the buck I've been after for three seasons with a re-used head. If I didn't feel confident in the head (that it was sharp and operating correctly)....it wouldn't have been in my quiver.